Trump rages on Twitter about losing popular vote: 'Campaigning to win the Electoral College is much more difficult'

President-elect Donald Trump has again insisted he still would have won the election if it had been based on the popular vote rather than on the Electoral College.

Trump defended his win in a tweetstorm Wednesday morning after The New York Times published an editorial advocating that the US presidency be decided by the popular vote.

The president-elect argued that "campaigning to win the Electoral College" was a much more "difficult" task than securing the popular vote, and he reiterated his previous suggestion that he would have campaigned differently if the election had been based on the popular vote.

Trump was formally elected the 45th US president when the Electoral College met Monday. But he lost the popular vote to his Democratic challenger, Hillary Clinton, by more than 2.9 million votes.

The presidency is decided by 538 electors, who are allotted to states proportionate to each state's population.

Much of the US population is concentrated in Democratic strongholds — on the coasts and in large cities like Chicago and New York City. The Electoral College therefore forces presidential candidates to focus their attention on states that could otherwise be overlooked, like New Hampshire and Wisconsin, and theoretically gives small states an important say in who runs the government.

The first candidate to reach 270 electoral votes wins the presidency, even if the candidate loses the popular vote. Trump received 304 electoral votes, and Clinton received 227, with the remaining seven voters choosing other candidates.